Working fluid for refrigerating apparatus



l0 working fluids in mechanical fluorine derivatives of so or phase ontop oi the refrigerant.

Jim. 16, 194

UNITED" dTAEd l ldl ldd PATENT OFWC 2,187,3ild

WUEHHNG ram FOR REFEIGERATING APPARATUS Harry M. Williams, Dayton,

llliio, assignor to No Drawing. Application September 6, 1935, SlerialNo. 39,453

9 Claims.

This application is a continuation-in-part of y two co-pendingapplications, Serial No. 465,029, filed June 30, 1930, and Serial No.524,- 409, flied March 21, 1931.

This invention relates to refrigeration and more particularly to workingfluids for refrigerating apparatus having" working parts requiringlubrication within a refrigerant circuit.

Heretofore it has been customary to use as refrigerating systems amixture of a refrigerant such as sulphur dioxide or ammonia with amineral oil which is immiscible for the most part with these refrig-=erants. Refrigerating apparatus has been delt signed for use with such aworlrine; fluid and dil flculties are often encountered with such reIrigerating systems when such working fluids are not used. When it isdesired to use a non-toxic, non-inflammable refrigerant such as one ofthe the aliphatic hydrocarlions such as the familiardifluorodichloro-meth one and the tetrafluorodichloro-ethane, difltculty has been encountered because of the fact that mineral oil iscompletely cible in all proportions with this class oi. refrigerants.

it is an object of my invention to provide non= tonic, non-inflammablewar-hing fluids for reirleerating systems having lubricants which arewhtolly or partially immiscible with the refrigeran ore specifically itis an object of my invention to provide a working fluid containing oneof the derivatives of aliphatic hydrocarbons, for example,difluorodichloro-methane or-tetrafluorodichloro-ethane with a lubricantwhere is wholly or partially immiscible therewith.

as one example of my invention, I employ dii'luorodichloro-methane andcaster oil as a work:- inc huid or charge for a refrigerating system.

iese two fluids have a relatively small mutual rnlscihility orsolubilityand when sumcient cas tor oil is provided in proportion to thedifiuorodichloro-methane, this worlrine fluid forms two layers or phasesoi liquid.

l have found that diiluorodichloro-methane and castor oil have a limitedaildnity for each other so that only a small quantity of castor oil willdisappear into the body of the refrigerant, the remainder helng tree inthis case as a layer There is usually a relatively small mutualmiscibility or solubility between the lubricant and the refricerant, andthere may be a slight amount oi refrigerant dissolved in the upperlubricant layer on top of the by of the refrigerant. In this upper layer(till. 252-5) or phase the lubricant greatly predominates since suchupper layer or phase is essentially an oily body, it is termed herein afree lubricant.

In the use of this working fluid, the content of the castor oil inproportion to the difiuorodi chloro-inethane may be readily controlledso that for any particular type of machine the free lubricent is of sucha quality as desired for the best operation of the refrigeratingmachine. This gives several benefits in operation such as high emciencyand in service the relative quantities of lubricant and refrigerant maybe more readily determined as in cases where additional changing isnecessary.

As another specific example of a working fluid I embodying my inventionI provide a fluid courprising, tetrafiuorodichloro-ethane and castoroil. These substances likewise have only a limited amnity for each otherso that only a small quantity of castor oil will disappear into the refrigerant, and the remainder ion a layer on top of the refrigerantcontaining: a slight amount of refrigerant dissolved therein. This upperlayer is essentially an oily body, and is termed herein a freelubricant.

Preferably the castor oil used in the before mentioned working fluid isone which has heen dewaxed by cooling the oil to extremely low tempcratures by refrigeration until the wax solidifies and then separatingthe liquid castor oil from the wax. If the castor oil used in theseworking? fluids containing either difluorodichloro-methane and castoroil or tetrafluorodichlormethane and castor oil has not been dew-"axed,i add a solvent for the was such as methyl or ethyl alcohol insufllcient entities to prevent the. was from solidifyinc or hecominuezvely viscom at the lowest temperatures encountered in the reirleersting system in which the were fluid is to be used.

As another specihc example oi" my invention I provide a woo-hue fluidcoinnrlsinc diiluoro: chloro-inethane and. clye. "l'his worlrine fluidlikewise form two layers, the one layer or phase being essentially a anoily hody, termed herein a free lubricant, while the other layer forms arefrigerant.

As another specific example oi my invention l provide a working fluidcomprising tetraduorodichloro-ethane and glycerine which lihewise formstwo phases, one of these phase or layers is an oily body, termed hereina tree luhrieant.

Preferably, I use chemically pure ylycerine. However, it the glycerinecontours wan, l add a solvent for the wax such as ethyl or thyl al ,r

cohol in suificient quantities to prevent the wax from congealing in therefrigerating system.

As another specific example of my invention- I provide a working fluidcomprising difluorodichloro-methane and diethylene glycol.- This workingfluid likewise forms two phases, one of which is a lubricant phase.

Another example of my invention is a working fluid comprisingtetrafluorodichloro-ethane and diethylene glycol, which likewise formstwo phases or layers, one of which is a lubricant phase.

While I have mentioned specifically difluorodichloro-methane andtetrafluorodichloro-ethane as refrigerants which are not miscible withthe lubricants mentioned namely in castor oil, glycerine and diethyleneglycol, these refrigerants are merely specific examples of the largeclass of refrigerants which are fluoro derivatives of aliphatichydrocarbons to which the present invention is applicable. Of this classof refrigerants, I prefer to employ the halofluoro derivatives of thealiphatic hydrocarbons which contain both densed refrigerant to theflooded evaporator and the evaporation of the refrigerant concentratesthe lubricant content of the fluid in the evaporator to such an extentthat a layer or phase of free lubricant separates from the refrigerant.This free lubricant in such .a system is returned to the compressoralong with the refrigerant by the use of some kind of device in theevaporator for withdrawing the free lubricant from this phase.

The direct expansion type of refrigerant apparatus and method, thecondensed refrigerant carrying a slight amount of lubricant is expandedinto a confined tube of a substantially uniform diameter where thevelocity of the evaporated refrigerant sweeps the separated lubricantback into the compressor.

all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A refrigerating fluid comprising a halofluoro derivative of analiphatic hydrocarbon and castor oil.

2. A refrigerating fluid comprising dichlorodifluoro methane and castoroil.

3. A working fluid for a compression refrigerating system comprising afluoro derivative of an aliphatic hydrocarbon and castor oil.

4. A refrigerating medium comprising difluorodichloromethane and castoroil free from superfluous wax.

5. A refrigerating medium comprising difluorodichloromethane, castor oilcontaining a wax, and a solvent for the wax.

' 6. A refrigerating medium comprising difluorodichloromethane, castoroil, and alcohol.

7. A working fluid for a compression refrigerating system comprising afluoro derivative of an aliphatic hydrocarbon and glycerine.

8. A working fluid for a compression refrigerating system comprising afluoro derivative of an aliphatic hydrocarbon and diethylene glycol.

9. A refrigerating medium comprising a halofiuoro derivative of analiphatic hydrocarbon and a liquid substantially immiscible therewithand having lubricating properties, said liquid being selected from agroup of lubricants consisting of castor oil and a polyhydric alcoholhaving a low pour point and a high vaporization temperature.

HARRY M. WILLIAMS.

